I have beat many guys with more HP under the hood by being consistent, the guys with superchargers have the problem of being to eager to push the pedal exiting the corners and most of them end up facing the other way.
Besides your driving abilities, tires, suspension and brakes are the key.
#1 in that list is TIRES, get the best that you can. You will be surprised how much you can improve your times with good tires. Some people go with the top suspension package and end up being beaten by almost stock cars but with good rubber.
#2 Brakes, get the largest you can afford or are permited in your class, get decent pads and have spare rotors at hand
#3 Suspension: little things can do wonders for a stock suspension:
a) Bushings: Front A arm bushings: steeda Offset bushings , rack bushings, decent end links.
b) CC Plates, more grip and better tire wear.
c) Adjustable shocks and struts are great tunning aids and will help adapt your car to different track conditions.